PLL 2G11 UV-C T5 Two Pin Type Lamps Ultraviolet Clarifier Bulbs or Sterilizer lamps help clear green water in a pond or aquarium. UV Bulbs kill bacteria and many viruses. Greenwater or single cell algae problems in Water Garden Ponds can be eradicated using a UV light clarifier. UV-C light germicidal Ultraviolet lamp or Ultraviolet UV Germicidal Bulbs help control the growth of algae. The increased water clarity improves fish viewing and it also improves the health of the fish. ? PLL Type H Quartz Glass 2G11 Base ? 253 NM Range ? Length does not include Pins (Standard Industry Specification) ? 18w [8.6" (220mm)] ? For Best Results Replace Bulb Every 8000 Hours or 6 Months (Average Life Span) ? Quartz Glass Construction ? For use in Pond Filters, Water Purifiers We sell Many UVC Bulbs online, Check out our Store!! Terms and Conditions. We use all approved forms of payment. Sales Tax will be added to all shipments based on regulations. We always try to combine purchases, please contact us directly for a personal service. You will be notified on the day that your goods have been dispatched via e-mail with tracking which is used on all purchases. Please note that if there are any problems, contact us first via e-mail giving full details of any problem along with your user ID. We use USPS and UPS as our chosen carriers shipments to Hawaii, Alaska Puerto Rico may incur surcharges, contact will be made to advise before shipment at which point the order can be canceled if desired. Orders placed on Saturday/Sunday Public Holidays will be processed next working day. We pride ourselves on excellent feedback, if any part of the buying experience is not to your satisfaction, please contact us to rectify before leaving feedback. By committing to buy you are agreeing to the Terms Conditions stated above.